KVM: Handle spurious acks for PIT interrupts

Spurious acks can be generated, for example if the PIC is being reset.
Handle those acks gracefully rather than flooding the log with warnings.

Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 7d04dd3..c842060 100644 (file)
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -228,7 +228,7 @@ void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
                                                 irq_ack_notifier);
        spin_lock(&ps->inject_lock);
        if (atomic_dec_return(&ps->pit_timer.pending) < 0)
-               WARN_ON(1);
+               atomic_inc(&ps->pit_timer.pending);
        ps->irq_ack = 1;
        spin_unlock(&ps->inject_lock);
 }